Artificial tooth



E. T. GOLDBERG.

ARTIFICIAL TOOTH.

APPLICATION FILED OCT- Is. 1918.

1 ,3 1 0,237 Patented July 15, 1919.

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ELIAS T. GOLDBERG, 0F BRIDGEPOBT, CONNECTICUT.

ARTIFICIAL TOOTH.

Specification of Letters Patent.

Patented July 15, 1919.

Application filed October 16, 1918. Serial No. 2 58,862.

To all-whom it may concern:

Be it known that 1, Emma T. Gonnnnno, a citizen of the United States, resid in at the city of Bridgeport, county of Fear eld, State of Connecticut, have invented certain new and useful Improvements in Artificial Teeth; and I do declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertams to make and use the same.

This invention relates to certain new and useful improvements in artificial teeth and more particularly to an improved means for securing or anchoring replaceable porcelain facings to metal or other backings.

It has been proposed to unite the porcelain facings to their backings by a tongue and ove or dovetail connection but this method has thus far proven impractical for the reason that the undercut groove in the porcelain would warp and become misshapened as a result of the irregular shrinkage during the baking of the porcelain. This lack of uniformity of the porcelain oove rendered it exceedingly diflicult to t a standard backing, and often the metal tongue would fit so loosely that the large amount of cement necessitated would soon crumble under constant use and thereby be useless.

It is the aim and primary object of this invention to overcome this difliculty by providin a metal lock between the porcelain and its backing.

The invention consists in securing a slotted metal lock member to the porcelain during the manufacture thereof, either by shrinking the porcelain about the metal when bakin the facing or by a cementitious binder, saiflock member 'being fitted in a groove in the back face of the porcelain and of such shape as to receive the metal tongue of the backing.

In the drawin Figure 1 is a ont elevation of a set of teeth in process of construction, certain facin havlng been omitted;

2 is a rear elevation of the improved porce ain facing;

Fig. 3 is a vertical section on line 33 of Flg. 1;

Fig. 4 is a horizontal section on line 44 of Fig. 1;

Fig. 5 is a vertical section through a medi fied form of facing especially adapted for a back tooth; and

Figs. 6 and 7 are end elevations of modi-- fied forms of the lock member.

Referring more in detail to the drawing, the porcelain facing 1 is formed with an undercut groove 2 in its back face, which groove preferably opens through one end of the porcelain bod in the form of a flared gateway, as i1 ustrated in Figs. 2 and 3. A metal lock member 3 is then inserted Within the groove 2 with its edges engaging beneath the undercut or overhanging sides of the groove. This lock plate or member 3 is secured in position by either relying on the shrinkage of the orcelain durino the baking process to rmly unite the pTate and porcelain, or by initially baking the porcelain and then inserting the lock member within the undercut portion with an intermediate application of suitable cement.

The outer end of the lock plate is longitudinally slotted, as at 4, to receive and embrace the neck or shank of a hook-shaped, headed stud 5 projectin from the metal backing 6. The head 0 this stud 5 substantially conforms to the pocket thus defined by groove 2 and lock plate 3 to afford a tight fit which may be maintained by a cementitious binder.

By the provision of the metal lock plate, metal will then fit metal and the certainty of a tight fit and joint is practically assured. The characteristics of the metal from which the lock plates are constructed are such that the same will not fuse or be affected by the heat required for the bakin of the orcelain. The lock plate is pre era'bly alf round or half tubular in cross section, having one side opened, but other shapes may be employed as indicated in Figs. 6 and 7 wherein the lock members 7 and 8 are tubular and of semi-cylindrical or polygonal cross section.

Fig. 5 illustrates a back tooth in which a wide 0 ening, constituting the gateway for the loc plate member, is provided. The cement binder would therefore be more exposed to outside influences but to avoid such exposure the backing 6 is downturned across the gateway to form a closure lip 9.

In constructing a set of teeth, the metal backings are assembled edge to edge and the gold or other reinforement 10 in an eplied thereto. The undercutslots or grooves in the porcelain faeihgs are filled with a cementitious substance and the entrance gates positioned relative to the headed anchoring studs for being slid intb position.

What is claimed is: v

1. An artificial tooth comprising a poreelain facing formed in its back face with a substantially dovetailed groove, and a'loek plate bent from sheet metal and having its side edges inturned to engage beneath the undercut walls of the groove and its inner end abutting the end wall of the groove, the outer end of said lock plate being formed with a slot narrower than the space between the outer edges of the grooves.

2. An artificial tooth comprisin a porcelain facing having a groove in its ack face, and a metal lock late eonvexing outwardly to close the space intervening the outer edges of the groove and having its edge portions 001110: at this patent may be obtained for five cents each, by addressing the seating on the botton of the gr ove, said plate spaced outwardly fiom the o'ttom of the groove to receive the head of a mounting stud between said groove bottom and the plate.

3. An artificial tooth comprising a porcelain facing formed with a groove in its back face 0 ening in a wide gateway through one end thereof, the sides of the groove be ing undercut,a metal lock plate inserted in the groove with its edges engaging in the undercut sides thereof, said plate being slotted adjaeent the entrance gate of the groove, and a metal backing hav ng a headed studfitting the groove beneath the plate with its shank disposed in the slot of said plate, the outer end of the backing being downturned to form a closure lip for the gateway of the facing oove.

In testimony whereo I affix m si ature.

ELIAS T. GOL B RG.

Commissioner of Patent",

Washington, D. 0. 

